In previous work, we demonstrated that the reporter gene cell fusion assay can be used to study Envelope glycoproteins from diverse animal viruses that fuse directly with the target cell (e.g., paramyxoviruses such as measles virus and canine distemper virus). The assay was also modified to screen for target cell molecules required for fusion (e.g., the HIV coreceptor CXCR4). We have initiated efforts to identify the receptors for other major enveloped viruses such as respiratory syncytial virus in the Paramyxovirus family. We have initiated a collaboration to obtain the genes for the relevant RSV surface proteins (F, G, and SH) to proceed with this effort.